CVE-2026-8201: A use-after-free vulnerability exists in MongoDB's Field-Level Encryption (FLE) query analysis component, affe

Routine

MEDIUM 6.4UPGRADE

CVE-2026-8201 is a medium-severity flaw (CVSS 6.4) affecting mongodb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A use-after-free vulnerability exists in MongoDB's Field-Level Encryption (FLE) query analysis component, affecting client-side uses of mongocryptd and crypt_shared. Triggering this vulnerability requires control over the structure of a client's FLE-related query. This issue impacts MongoDB Server’s mongocryptd component v7.0 versions prior to 7.0.34, v8.0 versions prior to 8.0.23, v8.2 versions prior to 8.2.9 and v8.3 versions prior to 8.3.2.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.4 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-05-13
Last modified	2026-10-26

Publisher (CNA): MongoDB, Inc. · Vendor: mongodb

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-13 04:17 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

mongodb mongodb UPGRADE

Affected: >= 7.0.0 and < 7.0.34 · >= 8.0.0 and < 8.0.23 · >= 8.2.0 and < 8.2.9 · >= 8.3.0 and < 8.3.2

Fixed in: 7.0.34, 8.0.23, 8.2.9, 8.3.2

Safe to downgrade to: a release before 7.0.0

1. Check installed version

apt-cache policy mongodb || rpm -q mongodb || mongodb --version

2. UPGRADE to 7.0.34 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mongodb

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mongodb

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 7.0.0 (Debian / Ubuntu)

apt-cache madison mongodb sudo apt install mongodb=<VERSION_BEFORE_7.0.0> sudo apt-mark hold mongodb

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mongodb sudo dnf downgrade mongodb-<VERSION_BEFORE_7.0.0> sudo dnf versionlock add mongodb

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8201?

mongodb: upgrade to 7.0.34, 8.0.23, 8.2.9, 8.3.2. Exact commands for each OS are on this page.

Is CVE-2026-8201 being exploited?

CVE-2026-8201 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8201 affect?

CVE-2026-8201 affects mongodb. Severity is medium (CVSS 6.4). A use-after-free vulnerability exists in MongoDB's Field-Level Encryption (FLE) query analysis component, affecting client-side uses of mongocryptd and crypt_shared. Triggering this vulnerability requires control over the structure of a cli

How urgent is CVE-2026-8201?

Priority 23/100. No elevated risk signals yet.

Software pages

MongoDB vulnerabilities

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References

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